Patent GB-653335-A (GB)
Title: Improvements in or relating to apparatus for sealing valved bags
IPC: B65B7/02
Filed: 1948-03-08
Abstract: 653,335. Filling and closing valve bags. ST. REGIS PAPER CO. March 8, 1948, No. 7085. Convention date, March 20. 1947. [Class 94(i)] In the filling and closing of valve bags formed with a valve sleeve 26, Fig. 14, having a layer of adhesive 26a on its inner surface, the sleeve is first spread laterally to bring its upper and lower walls into substantially parallel relationship, and the opposed wall surfaces then united by the application of pressure and, if necessary, heat. Alternatively, adhesive may be applied to the outer surface of the sleeve as a coating or lamination 26b, Fig. 13, and the margin of the sleeve folded inwardly prior to the spreading operation. As shown in Figs. 1, 2 and 18, two bags 27 and 27a are supported in tiltable chairs adjacent filling and closing apparatus, comprising two filling nozzles 22, 23 and two heat-sealing units 20, 21 mounted on pivots 28, 29, the unit 21 being shown in an inoperative position clear of the bag 27a which is being filled through the nozzle 23, and the unit 20 in an operative position for sealing the valve sleeve of the bag 27 which has been moved to the position shown in Fig. 2 after having been filled through the nozzle 22. Each sealing unit comprises a pair of spreader fingers 33, 34, Figs. 3, 6 and 8, pivoted at 35, 36 on a slidable carriage 37 and adapted to be opened against the action of a spring 39 by axial movement of a rod 49 which is slidable in bores in the carriage 37 and carries an expander block 40 on which are pivotally mounted arms 41, 42 urged outwardly by springs 45, 46 into engagement with rollers 47, 48 on the fingers. This rod may be locked in a retracted position by a pivoted spring-loaded ,latch 54 adapted to engage behind a latch plate 56 mounted on the carriage 37 and. to be tripped by engagement of a roller 59 at one of its ends with a block 58 secured to the housing of the unit. The carriage 37 is urged to the right by a spring 63 and may be locked in an inoperative position by a latch 66 pivoted on a fixed stud 67 and co-operating with the plate 56. A secondary latch 83 is provided to hold the carriage in an extended position. A mem ber 38 carrying, a sealing element 38a is mounted on rollers 71, 72 for axial movement beneath the carriage 37 and is formed with a keyway 61 for engagement with a key 60 on the carriage. This member is fitted with a rack 90 in mesh with a gear 89 which in turn meshes with a gear 88 on a shaft 81 on which is mounted an arm 70 carrying a co-operating sealing element 70a preferably a strip of rubber, and two spring-loaded, pivoted fingers 70b which assist in flattening the bag tape 27b, see Fig. 5 (not shown). Thermostatically-controlled, electric heating elements may be fitted below the element 38a. The arm 70 is actuated through linkage by a pneumatic cylinder 91, Fig. 2, controlled by a valve 95, Fig. 1, this valve also controlling pneumatic cylinders 104 which operate through toggles 102 to swing the units 20, 21 about their pivots. In operation, after the bag 27 has been filled and moved to the position shown in Fig. 2, the valve 95 is operated to swing the unit 20 into operative position and start the closing movement of the arm 70. The initial movement of the arm causes a lever 80 secured to the shaft 81 to engage a spring- loaded catch 68 on the latch 66 and trip the latch, thus allowing the carriage 37 to move to the right under the influence of its spring 63 to an extended position in which the contracted spreader fingers 33, 34 are inserted in the valve sleeve, see Fig. 9 (not shown). The latch 83 then falls into position to lock the carriage in the extended position. At the same time, the member 38 is moved to the right by the rotation of the gear 88, and a forked member 82 on the shaft 81 engages rollers 52 on the rod 49 to move the latter to the left and effect opening of the fingers to spread the valve sleeve, see Fig. 10 (not shown), the rod being then locked in a retracted position by the falling of the latch 54. The latch 83 is now lifted by the engagement of a roller 86 thereon by a lever 87 on the shaft 81, and the carriage 37 is entrained by the rod 49 through the expander mechanism and is moved to the left to withdraw the fingers as the element 38a moves into position beneath the valve sleeve and the element 70a and fingers 70b engage the top of the sleeve to complete the seal, see Figs. 11 and 12 (not shown). Thereafter, further movement of the rod 49 to the left causes the roller 59 on the latch 54 to engage the block 58 and the latch is tripped to allow return movement of the rod and the closure of the fingers. During the latter part of the inward movement of the carriage 37 the latch 66 reengages over the plate 56 to retain the carriage in a cocked position ready for the next operation. The valve 95 is finally operated to cause return movements of the arm 70 and sealing unit to their inoperative positions. The supporting means for the bags comprises two chairs 116 and 122, Figs. 18 and 20, mounted on pivots 117 for tilting movement relative to a supporting frame 118 and urged to an untilted position by springs 119, the chairs being movable alternately by relative axial movements of the frame and a cam 123 having raised portions 123a, 123b which engage rollers on lever arms 124, 125. In the tilted position the rear ends of the bags rest against a stationary ledge 121. Each chair is provided with a yoke member 120 carrying a toggle-operated clamp 108 which is actuated by a cam, not shown, to grip the bag tape 27b during the filling operation and is opened by an arm 126 on the arm 70 just prior to the sealing operation.